Game outcomes on gaming devices are typically determined at random where winning outcomes are awarded to a player in the form of money, credits, promotions, prizes, or other incentives, and losing outcomes typically result only in a lost wager. Player excitement is typically generated by providing the possibility of winning large awards for a relatively meager wager. Indeed, for most players, the excitement and gratification of gambling is tied to achieving wins. While these players will endure certain periods of loss, players will often press the spin and/or bet buttons as quickly as possible to pass through the losses to get to another win. Business principles require that most outcomes not be large winning outcomes for the player. Thus, many gambling sessions include extended periods that are devoid of large winning outcomes. Even during a more balanced gaming session, a great portion of time on a gaming device is spent watching reels spin (poker hands played, etc.) with a resulting loss. It is understood that these losses must be balanced with giving the player some incentive to keep playing, and casinos look for ways to maintain player interest in the gaming device besides providing wins.
Gaming machines typically operate with a random number generator (RNG) that generates a numeric code by which to determine a game outcome. For example, a slot machine is often constructed of 3 reels, with a multiplicity of symbols placed on each. Certain combinations of symbols that align on a center payline are designated as winning outcomes and are assigned award amounts. Other outcomes are losing outcomes that generally are not associated with an award. If each reel is equipped with 22 positions, there are 22×22×22 (10,648) possible combinations that can appear on a single payline.
By varying the quantity and value of symbols placed on each reel, a variety of payback percentages are obtainable. To help create more flexibility in generating payback percentages, some games use longer reel strips with more symbols or use virtual reel strips that map one or more possible outcomes to each position on a reel strip. Many games are created with multiple paytables that having varying payback percentages. Casino operators are typically able to select a particular paytable for each game. Thus, casinos in popular locations may choose paytables with lower payback percentages during peak days or hours and select paytables with a higher payback percentage at slower times to entice more gambling. Additionally, casinos in more remote locations may choose paytables with significantly higher payback percentages to attract players to their game floors. Hence, the flexibility afforded by providing multiple paytables in a single game is important for casinos.
Over the past 15 years or so, bonusing has become a popular method for incentivizing players. Bonuses can be controlled by a bonus engine (also known as a bonus server) to decide when to award a bonus at a particular game and how big that bonus award should be. Bonus wins of this nature are not funded by the base game's paytable. These bonuses, while exciting when received, are typically fairly large-value awards and hence are won relatively infrequently. Hence, they do not typically play a large role in most gaming sessions.